Telephone system



E. D. BUTZ TELEPHONE SYSTEM Filed July 31, 1923 2 Sheets-Sheet l l.- v k F'Fg hue/vial.- Edna/dD. 50/2.

Dec. 29, 1925-, 1,567,236

E. D. BUTZ TELEPHONE sys'rizx Filed July 31-, 1923 2 Sheets-Sheet 2 Patented Bee. Z19,

iJhilThl TTES 1,567,236 PATENT OFFICE.

EDWARD D. BUTZ, OF PALISADE, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, IN COB-PDRATED, OF NEW YORK. N. Y..

A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Application filed July 31, 1923. Serial No. 654,804.

To all whom it may concern:

Be it known that I, EDWARD D. Bu'rz, a citizen of the United States, residing at Palisade, in the county of Bergen, State of New Jersey, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to discriminating tone circuits for automatic telephone systems and is an improvement upon Patent No. 1,265,225, of May 7, 1918 to T. G. Martin.

These tone circuits are for the purpose of informing special operators of the character of the calling automatic lines when such lines originate calls to these operators positions, as, for example, to order up a toll connection.

A certain tone will indicate to the recording operator that the line is denied toll service, for example.

In the arrangement of said patent the tone sources are permanently connected to the sleeve conductors of the subscribers lines. lVhen an intermediate distributing frame is used between the line switches and the connector banks, relatively long cables are necessary. These cables also carry sleeve conductors of lines which are not connected to tone sources that is, sleeve conductors of lines which, for example, are not restricted. If the tone sources are permanently connected to the sleeve wires of re strieted lines tone current is induced from these sleeve wires to the sleeve wires of nonrestricted lines, and when a call is originated from a non-restricted line and the line switch of such line and selectors extend the line to a recording operators position, the operator will upon responding to the call hear a tone and will refuse to put up the connection requested.

The object of this invention is to provide a 'tone circuit which will be free from this objection and which will also reduce the load on the discriminating tone machine.

In accordance with this invention the tone sources at the main oflice are normally disconnected from the sleeve conductors of the lines and electromagnetic meansis oper ated only upon the closure of a calling line circuit in originating a call to connect its tone source to the sleeve conductor of such a line, the closureof said line circuit also serving to operate an automatic switch to extend the calling line to a trunk which may lead to numerical switches by means of which an operators position is selected. The tone current passes over a circuit including conductors of said switches and upon the response of the operator and the connection of her head set to the trunk the tone current gives the operator a distinctive signal in her receiver to indicate the character of the calling line. Means is provided for preventing the closure of the called line circuit when the called party removes his receiver from connecting the sleeve of such line to its tone source if any is provided for such line, since ii the line is called, the tone circuits are not needed.

In the present embodiment of the invention line switches of the plunger type are provided for automatically extending calling lines to idle trunks, the plunger magnet armature in addition to forcing the line and trunk springs into engagement, also serving to close a switch to connect the tone source with the sleeve of the calling line. When the line is selected by a connector this armature is not actuated, the line relay being disconnected by other armatures of the plunger magnet and consequently the tone source associated with the group to which the called line belongs is not connected to the sleeve of such line.

Referring to the drawings, Fig. 1 shows a subscribers line, a first and a secondary line switch and a repeater, and Fig. 2 shows a selector and a recording opcrators trunk.

The automatic substation A (Fig. 1) terminates at the central office in the primary line switch LS. If the subscriber at substation A wishes to make a call to an operator, for example a recording operator, he operates the primary and secondary switches LS and L'S, the repeater R and selector S to extend his connection to a recording operators trunk circuit RT. No connection is made through this trunk, however, but the operator is simply given the order over it. The calling subscriber then hangs up his receiver and breaks connection with the trunk RT. The operator then calls back to the calling line by means of automatic toll switches (not shown). These switches and circuits may be of the type shown in said patent to Martin.

lVith this general description, itishelieved the invention will be most readily understood from a description of the operation. When the subscriber at substation A wishes to make a call he does so by removing his re ceiver from the switchhook. The hook thereupon closes a circuit from ground through armature 100 of line switch plunger magnet B, line 101, the substation loop, line 102, armature 103, and relay 1%. of the primary line switch LS to battery and ground. The relay A thereupon attracts its armature which operates to close a circuit from ground through the pull down winding of plunger magnet B to battery and ground at the master switch M as disclosed in the above mentioned patent. The magnet B thereupon operates the plunger arm 105 and cut-off armatnres 100, 103. The plunger arm operates to cause the plunger to press the bank springs of the prin. ary line switch together, while the armatures 100, 103 operate to disconnect the relay A from the line, but relay A. is made, slow to release so that ground from the repeater will be connected to the holding winding of magnet B in the well-known manner before the original energizing circuit through the operating winding is opened. When the bank springs 106, 107 are forced into contact by the plunger of line switch LS a circuit is closed from ground hrougn said springs, pull-down winding of mag net 0 of the secondary line switch LS armature 108 of magnet C to grounded battery at secondary master switch M as disclosed in the above mentioned patent. The magnet C operates the plunger arm 109, which closes, the bank springs in the switch LS, and also shifts armature 108 to its front contact, whereby the upper winding is connected to battery through the lower winding, thus c. tablishing a holding circuit for the switch LS independent of the contacts of the relays ot the master switch ct. The coinbin fl operations of the switches LS and LS e1:- tend the line to a repeater B. When. the circuit is thus extended to the repeater R its line relay 110 is energized over the calling line circuit. The relay 110, upon energizing, closes a circuit for operating slow to release relay 111 which returns ground on the sleeve 112 to provide a holding circuit for magnet B of the primary line switch before its energizing circuit is opened by the release of slow relay A in the well-lrnown manner. This circuit includes the upper winding of coil 113, a normal contact of relay 115, the left alternate contact of relay 111, sleeve wire 112, contacts of the line switches LS, LS, sleeve wire 12S, lower holding winding of magnet B to battery. Another result or the energization of relay 111 is the closure of a circuit from ground on the sleeve wire through the upper Winding of relay 115 by way of conductor 114. The relay 115 is so constructed and adjusted that it cannot be operatively energized by one winding alone but requires the combined energization of both its windings to cause it to attract its armature.

The operation of relay 110 closes a circuit through the line relay 200 of the selector 5 (Fig. 2) as follows: battery, 200, 201, 1.16, 117, 115,113, 118, 119, 120, 121, 205, 200, ground. The relay 200, upon energizing,

completes a circuit for the slow-torelease relay 206. lVhen the subscriber at substation A operates the calling device for the zero or other digit assigned to the recording operator, the circuit of the repeater relay 110 is intermittently broken in response to this operation of the calling device. The relay 111 of the repeater, being slow-to-release, does not deenergize during the momentary interruption of its circuit by the relay 110. The first retraction of relay 110 closes a circuit for slow-to-release relay 122 which remains energized during the intermittent operation of relay 110 to disconnect the condensers 12-3, 124 from the outgoing conductors 116, 121 for the well-known purpose. Each retraction of the armature of relay 110 opens the circuit of the impulse relay 200 of the selector S, which in retracting its armature transmits impulses to the vertical magnet 20? of the selector in the well-known manner. vertical magnet operates in response to the impulses received over this circuit to raise the shaft and wipers. The relay 208, which is included in circuit with the vertical magnet is energized by the first impulse, but being a slow release relay does not allow its armature to fall back until after the last impulse has been delivered. In its energized condition the relay 208 closes a circuit for the escape magnet 209. This circuit is broken when the relay 208 deenergizes after be last impulse has been delivered to the vertical magnet and the private or escape magnet thereupon deenergizes and permits the side switch to pass to the second position. In passing from first tosecond position the side switch wiper 210 disconnects the battery from the vertical magnet and closes a circuit through the rotary magnet 211. The rotary magnet will then continue to operate in a manner similar to that of a buzzer to rotate the wipers step. by step as long as the side switch remains in second position. As soon as the rotary magnet energizes the first time, a circuit is closed from ground at its upper armature to battery through. the escape magnet 209. The escape magnet is energized over this circuit and is again deenergized when the rotary magnet deenergizes after having rotated the wipers the first step, provided the first trunk line upon which the selected wipers are rotated is idle. If this trunk is busy, however, the private wiper 213 finds the test contact 222 which it engages provided with a guarding ground po- The until the contacts of an idle trunk are reached, whereupon, the private magnet deenergizes, permitting the side switch to pass to third position and break the circuit of the rotary magnet to stop the switch. Vhen the side switch wiper 210 reaches its third position a circuit is closed from battery arm 210, relay 202 to ground at the inner armature oi? relay 206. The relay 202, upon energizing, op-

crates its armatures 201, 205 to disconnect the impulse relay 200 from the line and to en:- tend the connection through the wipers 21s. and 215 to the trunk RT. The relay 216 thereupon becomes energized over the calling line loop and operates to close a circuit to signal the operator from ground through the left winding of relay 217, normal con tacts of key K, upper winding of relay 218, upper armature of relay 216 contactof key K and right winding of relay 217 to battery. The relay 217, upon energizing, closes the circuit of lamp 219 to signal the operator. The combined energization of relays 216 and 218 provides a guarding ground potential at the selector private bank contacts 222 of the trunk by completing a circuit from ground through the lower winding of relay 218, terminal 222, brush 213, side switch wiper 212. relay 202, side switch arm 210 to battery. This circuit maintains the relay 202 energized after the selector impulse relay 200 has released slow relay 206. The lower winding of relay 218 has'a low resistance and a small number of turns, so that it alone will not cause relay 218 to operatively energize. Its function will be explained later.

The operator is enabled to determine the character of the line calling in the following manner: It will be seen that the circuit by means of which the line switch LS is held in its operated position extends from ground at repeater B through the upper winding of coil 113, normal contacts of relay 115. left alternate contact of slow relay .111, sleeve wire 112, contacts of line Switches LS, LS, holding winding of magnet B of switch L8 to battery. Branched off from sleeve wire 128 at point 129 is a conductor 130 to which a contact spring 126 is connected. l Jhen the line switch LS plunged, it operated to close springs 125, 126 together, thus connecting the secondary of a discriminating tone coil 132 to the sleeve wire 128. This tone coil is common to the group of lines to which line A belongs as indicated. Tone coil 13? is of a different characteristic and will be common to another group of lines similar to line A.

The calling and called terminals of the local conductors are cross-connected at the l. D. F. in order that the characteristic tone of the line may be disconnected from :1 called line in a manner hereinafter described.

At the repeater the lower winding of coil 113 is included in a bridge across the conductors 116 and 121 as described which conductors are now connected through the selector S of the operators trunk. Thus the test tone current flows from the secondary ot the induction coil 132 through the upper winding of coil 113 to ground and induces a current in the loop including the lower winding of said coil and the trunk line which will be heard by the operator when she connects her talking set with the line to answer the call by throwing key K to the left. This circuit may be traced from conductor 113, 117, 115, 113, 113, 119, 120, 121, 204, 203, 215, 223, 224, 225, 226, 227, 223, 229. 230, 231, 232, 233, 234, 235, 236, 237, 233, 214., 201, 116. thrown to the right, the relay 217 is disconnected from the line but the head set remains connected in circuit. This results in the release of relay 218 which releases placing a direct ground on the sleeve multiple 222. After the calling subscriber has given his order to the operator, he hangs up his receiver, releasing the automatic switches brought into use by him and the operator sets up the desired connection by calling back onto the calling line in the reverse manner. The release of the tone switch L opens contacts 125, 126, thereby disconnecting the tone source 132 from conductor 128.

The trunks leading from the switches LS might lead directly to selectors 9 without going through a repeater R;-that is, the conductors 116, 121 might be connected directly to the line switch bank springs 131, 135. The bank spring 136 would then be connected to the contact 220 in the selector and the holding circuit of the line switch LS would then include the lower winding of relay 218 at the trunk RT instead of the upper winding of coil 113 at repeater R. The tone current would then pass through the lower winding of coil 218. In this case the operator could disconnect the tone current from the trunk while conversing with the calling party. By throwing the key K to the right the relay 217 is disconnected from the trunk when the operators talking set is connected therewith. Relay 218 would then release and cut its lower winding out of the circuit of induction coil 132 thus removing the tone current from the trunk, and by its continuity contact a holding ground is maintained on the third wire to hold the lower winding of magnet B energized to hold the connection.

When the key K is Relay 115 in the repeater is provided to reverse the direction of the flow of current in the calling line for metering or supervisory purposes when the selector is set to pick out a connector and the back-bridge relay operates on the response of the called party. This back bridgerelay by reversing the direction of current flow in the trunk operates relay 115 which reverses the battery connections through relay 110. When subscriber A is called, ground is connected to the called local, conductor 139' and operates relay B, through its lower windin The current flow through this winding is only sufficient to operatethe lower set of springs 100 and 103' which open the circuit for relay A, thereby keeping the upper winding of the relay from receiving sufficient currentto operate the plunger arm 109, and thereby connect tone to the sleeve conductor of the called line through spring 126.

at is claimed. is:

In atelephone system, telephone lines of different characterga local conductor for each line, a tone source for certain of said lines, and means actuated by the closure of one of said certain calling lines for connecting its local conductor to said source.

2. In a telephone system, telephone lines of different character, a local conductor for each line, a tone source for certain of said lines, and means actuated by the closure of one of said certain calling lines for connecting its local conductor to said source and for disconnecting the same therefrom upon the opening of the calling-line circuit.

3-. In a telephone system, telephone lines of different character, a local conductor for each line, a tone source for certain of said lines, means actuated by the closure of one of said certain calling lines for connecting its localconductor to said source and for disconnecting the same therefrom upon the opening of the calling line circuit, 'an operators position, means for extending calling'lines to said position, and means at said position responsive to said tone current.

l. In a telephone system, telephonelines of different character, a local conductor for each line, atone source for certain of said lines, means actuated by the closure of one of said certain calling lines for connecting its local conductor to said source, an operators trunk, means for automatically extending 'said calling line to said operators' trunk, and inductive means for transferring said-itone source from said local conductor to the talking conductors of said operators trunk;

55. In a telephone system, telephone lines of diflerent character, a local conductor for each line, a tone source for certain of said lines, means, actuated by the closure of one of said certain calling lines for connecting its local conductor to" said tone source, an

messes operators trunk, means for automatically extending said calling line to said operators trunk, a signal therein, means for operating said signal upon said seizure of said trunk, inductive means for transferring said tone source from said local conductor to the talking conductors of said operatofis trunk, an operators telephone, and a key for connecting said trunk to said telephone.

6. In a telephone system, telephone lines of different character, a local conductor for each line, tone sources of different character, and automatic. line switches adapted when actuated by calling lines to connect their local conductors to the corresponding tone sources, and when released to disconnect saidlocal conductors.

7. In a telephone system, telephone lines of different character, a local conductor for each line, tone sources of different character for said lines, and plunge-r line switches having contacts actuated by the movement of the plunger-s when actuated by calling lines to connect-their local conductors to the corresponding tone sources, and released to disconnect said local conductors.

8. In a telephone system, telephone lines,

a. central office wherein said lines terminate,

local conductors, an intermediate distribut-.

ing frame for facilitating interconnection of said terminals, a tone source at the central otfice, trunk llnes, automatic switches for extending calling lines to said trunks, and

means controlled by said automatic switches for applying tone current to the local conductors.

10. In a telephone system, telephone lines, line relays for said lines, a central oiiice wherein said lines terminate, local conductors for said lines at said central oflice, calling and called terminals for said local conductors, a tone source at the central office, trunk lines, line switches for said telephone lines, means for actuating said line switch upon the energization of the line relays on originating calls toextend the lines to idle trunks and to connect the local conductors thereof to said tone source, and means actuated by the closure of called lines for disconnecting their line relays without connect; ing said source to the called line local conductors.

11. In a telephone system, telephone lines of different character, means by which an operator can answer calls from any of said lines, means for indicating to the operator the character of the calling line including an identifying circuit for connection with apparatus individual to said lines, and means for closing said circuit only on originating calls.

12. In a telephone system, telephone lines of different character, means whereby an operator may answer calls from any of said lines, means for indicating to the operator the character of the calling line including a tone source for connection wlth the sleeves of the lines, and means for applying the 1 In Witness whereof, I hereunto subscribe 20 my name this 27 day of July A. D., 1923.

EDWARD D. BUTZ. 

